You have two main options on how tho do the trek to Everest Base Camp, you can either do it through an agency or do it yourself.
Doing an organized tour through an agency is easy but expensive, you will probably be in a big group with someone carrying your bag and organizing where you stay.
Doing it yourself is not hard and plane tickets from Kathmandu to Lukla is the only thing that you have to organize. You follow a very clear path, everybody stays in the same little “towns” with many tea houses, it is not necessary to pre-book anything. …
related – our Everest Base Camp / 3 Passes information page