As you know War Thunder has a built in replay tool, it usually saves your last 10 or so matches by default, unless you uncheck the option to autosave replays.
If you rename, a replay it will save it indefinitely.
In your hangar, you can go to the menu options and there is REPLAYS tab that has keyboard controls (hotkeys) for replay's controls, so you can change views and even the player you are viewing. some very nice video clips can be made from these replays.
There are several free to use video editing software and recording software that are easy to learn and use.
Windows movie maker to make, edit, publish videos , its free and included in windows, very easy to learn and use.
and for recording I use Bandicam. It sis free with full controls in the free version , the only thing the free version limits in your recording to 10 minutes max ( which is fine most clips are short anyway or you can combine two or more 10 minutes ones if you need a long recording) and it will not allow you to remove their Bandicam watermark in your recordings , in the free version, in the pay version you can replace it with a custom watermark of your own or just turn it off.
you find that at www.bandicam.com
I have not experienced any lag or FPS drop running this in the background whenever I want.
easy to learn , you can set custom hotkeys for screenshots and/or recordings, and shows FPS in game while recording/playing
I find it works great with recording game, and ventrillo, it will allow you combine all the sound in one file with the game(movie clip) or create separate sound files for the game, vent , your voice etc... so its very versatile with the sound files, which I like.
Some prefer FRAPS, which also has free version , but i believe their free version limits your clips even shorter.
Anyways thought I would share.
ALSO BE SURE YOU RECORD ANY REPLAYS YOU WANT TO KEEP, BEFORE NEW VERSION PATCHES, replays from previous version wont work anymore when a version update comes out.
for example right now you want to record any version 1.37 replays you want to keep, when 1.39 comes out they will not play back in game anymore, so you wont be able to record them, without keeping a copy of WT 1.37 on your computer (9GB-10GB of space)