if you want to download planes click on the download button. once the download is completed click on open. then your computer might say that which program you want to open it with. then click select from installed program and search simple planes click on the sp icon and then it would open game and download the plane. you only have to do this once and sorry for my bad english

if you have the game download the craft and save it @VChart

@MechWARRIOR57
Then, how to download to computer?

Well a easy way to do this would to upload the build as a unlisted post then when you need to get it for your computer you go to the unlisted post and bam