The Chambers "kits" are top quality, plus dealing with Jim Chambers and his family is a win win in every respect. With a Chambers kit you will receive the makings of a period and historically correct project. Any kit on the market requires a careful approach to the build if you want a good result. To complete the kit you will need to educate yourself on light metal and woodworking skills, inletting and relief carving techniques. You will also need to purchase some tools to complete the project. On all of these kits you will need to carefully move the barrel back some and then inlet the tang (chisel work), you will need to enlarge the pre-carved lock mortise and bring the lock in deeper into the inlet until it is in proper relation to the barrel/touch hole. You will need to do pretty much the same with the other inlay mortises such as the entry and ram rod pipes, complete the installation of the nose cap and all other furniture such as the trigger guard and butt plate. While these components are pre-inlet they require careful enlarging and finishing to final fit.
If doing all of that seems overly intimidating then the job is probably not for you. But remember that many beginners have completed a kit as their first project so you're not alone, a kit is an excellent learning experience. You are not alone either in the sense that loads of help is available here on ALR and you've but to post your questions to receive excellent advice on any aspect of your build. Then too you can browse the ALR Tutorial section for information on building techniques and the ALR Library for photos and examples of the longrifles of old.
Good luck and welcome to ALR, you have came to the right place to learn.
dave