File size

I searched and searched, but I coudn't find a strait answer (found some topics with no answer anymore since nov and such :O ) ..
I have a problem and I'm a really computer noob.
Today I made a movie and I editted it in davinci resolve 15. Then I went and wanted to deliver.
Many, MANY crashes later, I finally got a movie, but it is 15gb (it's just a 15min movie of me playing a game :O )
The 15gb is probably also the reson the program kept crashing.
How can I change the settings that the media file will be around 1 a 2 gb?
If you need specs, please tell me which and then I will ask the guy who helpt me build the pc what the specs where.
I have a problem and I'm a really computer noob.
Today I made a movie and I editted it in davinci resolve 15. Then I went and wanted to deliver.
Many, MANY crashes later, I finally got a movie, but it is 15gb (it's just a 15min movie of me playing a game :O )
The 15gb is probably also the reson the program kept crashing.
How can I change the settings that the media file will be around 1 a 2 gb?
If you need specs, please tell me which and then I will ask the guy who helpt me build the pc what the specs where.