In terms of getting your heart rate up and building strength ( therefore maximising fat burning) at home, there's lots you can do. This is a very quick guide to get you started

seconds interval by runloop

Firstly download "Seconds" timer app on your phone ( or similar interval based workout timer). Play the Tabata Timer workout. This does 20-second intervals and 10 seconds rest - very intensive but using the app gives clear visual indicators when to start and stop and acts as a motivator to keep going until the end of the interval. It also shouts out the next exercise you should be doing so there should be no need to stop. It's designed as 11 minutes with no breaks other than the designated rest periods but you can create your own shorter custom workouts.

If you have Alexa or google say "Play Rocky Tabata Songs" to have the exercise music linked with that so there are audible timers when to relax. I think the app will let you play music direct but this is the quick-quick guide. Even if you don't like the music it doesn't matter as it contains the bells and countdowns to know when to start and stop. There's loads of other Tabata music options but you need the ones with the audible timers.

As for the exercises, there are lots but the important ones are:

squats(Lower Body -LB) - works the glutes and legs. Glutes are the powerhouse muscles of the body and if these are strong a lot of postural issues can be corrected. Worth checking a YT video to understand the correct form as it's such a key exercise

lunges(LB) - works similar muscle groups but works the glutes in 3D so balance is required. Hold on to the worktop if needed for balance. Lunges also stretch the hip flexors in the opposing leg which is needed if you are sitting all day. Correct form is up and down not forward and back which puts too much strain on the knees

planks( core) - now a staple for core strengthening with lots of variation but get someone else to check you are properly planking and not piking. Easier variation is on your knees. Checkout YT for all the easier and harder options eg. side plank, rotating side plank, rotating side plank with a weight

press-ups( UB and core) - press-ups involve doing a plank so its also an all-round bodyweight exercise. Again lots of variations beginning with on your knees going right through to handstand press-ups

dips(UB) - excellent for triceps which is a muscle twice as large as the bicep and often neglected. Dips can be done off a worktop counter, a sturdy table and to make much harder - feet elevated. Harder still put a weight on your lap. To start off a dip on a box ( like a stepper) and if you need to momentarily sit at the end of each dip that's perfectly fine for now. ( Aim to stay in the air longer term) 

For bodyweight exercises there are obviously lots of others - here's a more complete list but the above are the main ones for now 

If you're thinking of buying strength equipment there's probably only one you need - a kettlebell.Kettlebell Swing

Actually you'll need two - a heavy one for the swings and a lighter one for single-arm work ( eg. bicep curls, military press) . You can buy cheapy vinyl and fill with sand which is fine or more expensive metal ones. I think Argos do a set of 3 if they're not already sold out

Here's a full list of exercises you can do ( the site is currently under development but I think current circumstances necessitate a pre-release)  The main ones that work the whole body are swing, squat and press, renegade row, lunge. All of these can be incorporated into the above Tabata exercise set. Those exercises are the ones that most address the postural exercises caused by increased sitting which will be happening a lot in the next few months

So, 10 minutes or even 5 minutes at a time is all you need. If it's 5 minutes, do three times in the morning, three times after lunch or every hour after 9 am.  If it's 10 minutes - twice in the morning ( every 90 minutes), twice after lunch. The key thing is that during the 5 minutes / 10 minutes to absolutely go for it so that you are quite exhausted at the end. There should be no need to change out of normal clothes as it's too brief but it will mean you can keep doing these through the day. If done properly it's as good as going to the gym as it spikes your heart rate and builds strength

Also, check out the 50 tips sheet to see how to be more active throughout the day during this very strange period we find ourselves in. Even if you not normally an exerciser, for your mental health, exercise definitely helps