Reinstall Mac OS

I think I messed up big time with my computer.

I was trying to erase and reinstall MacOS, on a MacBook Air 2014.

When I performed the Command R and I erased the Mac OS which was Mojave, the computer shut down and when I reopen appeared OS X Maverick. (don't know why, if I erased more than I was supposed)

Now, when I go to the installation screen, and I agree to wit T&C and I press continue it shows under of "Install" a little title saying : "Select the disk where you want to install..." There is no disk.

So I have decided to do the command R again, and I get to the screen where I can decide to choose and I choose Disk Utility. It shows 121.33 GB APPLE SSD SD0128F. So I thought I could restore, being the source Apple SSD SD 0128F Media and I was wondering if for destination I could choose OS X Base system, since the other alternative is the same as source... which for me doesn't make much sense.

So I am kind of stuck here, any help would be much appreciated. Oh and if you could tell me what I could next I really would appreciate.

Thank you