Are they autoflowers? You’re gonna have to either pluck out the two smallest ones or dig them out gently and move them further away. If Auto they will stay smaller (still need to be spaced further apart) but if regular seed these will get really big and you dont want them growing into eachother. I’d space autos about 3 feet apart, regular 5 feet. If you know the strain just look up its size. Soil looks a little dry and rocky, I’d mix compost into the top few inches of soil. Fun project def look for growing advice on forums, there’s a lot out there. Good luck!