I'd suggest you play with it for a week or so on dummy patients (plan on maybe 20 hours of play time). You can ask AC for an online demo session that took a couple of hours for us. It was helpful after we knew the basic stuff and had started formulating questions. We were surprised that our questions at that point were more sophisticated than we anticipated, and that we already had figured out the big stuff. Then import your patient database, and start using it but print everything and put in paper charts (that way if you REALLY mess up you can just re-import and no harm done). Do that for 1-2 weeks. Then go live.
Lots of differing opinions as to how to start. Some suggest just starting with the basic Hx/Px entry, and keep paper for orders and prescriptions, etc. for some time. Some of us "went all the way" from the get-go. Many people scan in and import their entire old chart. Some of us leave the old chart on the shelf and import only new items. Most of us seem to use some electronic faxing system, and some of use UpDox as a patient portal/fax system. The list goes on.
We are a 4 provider office, and found that the workload for the entire office changed greatly, and that this was a huge part of the changeover effort. We found it it NOT just the electronic equivalent of paper, but an entire new way of looking at documentation. Everyone in the office had to re-learn their job.
There are allergists on this site, and there have been postings on how to import an allergy testing sheet and other specific tasks. You can search for "allergy".
The permutations and combinations of things to have to learn and solve can get pretty large, and it will may a bit overwhelming at first. It will fall into place. Cut yourself some slack in the process. As my partner says "You can read about playing hockey for years, but the only way you learn how to play is to get out on the ice and accept that you will play badly for some time."