Question about companion planting

Hi, how are you? I started to do companion planting recently. Yesterday, I planted both beans and corns on the rows next to each other. However, I did not know how closely I should have planted them together. In my case, I planted them about 25 to 30 centimeters apart, but I just did that because I did not know what the proper distance between those plants should be. I will be planting herbs and vegetables in companion planting scheme later on, but the websites I have been looking at don't really mention about how far apart those companion plants should be planted, or how they should be planted. For instance, I am wondering when you plant herbs like basil around tomatos, should basil be planted to encircle the tomatos? Thank you, and have a nice day.