As much as I wish it were, it's not a... training class :-)
You are going to have to do some research yourself. We can help with some answers etc and some can provide links but if you want to become an expert in building Agents it's going to take more than asking here.
There is no "checklist" as there are many variables in what you need, since we do not even have any idea of agents you want to build, environments, data sources you will use etc.
All of these you can search for yourself as well and will need to especially if you have never built them.
You will need
1. Determine who will be able to create agents
2. Determine what agent types (Teams, M365, SharePoint, SDK Based, Embedded, Power Platform etc)
3. Determine who can use them, who can build them
4. Determine the licenses you need based on where it will be used
5. Determine your Credits (pay as you go, buy bundles)
6. Determine your development plan, your ALM, your migration
7. Data Access, DLP Policies
8. Governance, Security, Authorization, Authentication
9. What to turn off, what to block
10. Do you support AI Builder?
11. What version of ChatGPT etc
12. Building your own models, training, deployment
13. Will you use managed environment, how to configure for multi-tenant
14. Data, Log, file allocations in environments for DV for CP
and so on.
Its a very large ask and not a possible one to just do over essentially chat.
You guys need to hire an expert to guide you through all of this.
If these suggestions help resolve your issue, Please consider Marking the answer as such and also maybe a like.
Thank you!
Sincerely, Michael Gernaey