And Don(working in the bank) wants to talk about your plan. So he want to have lunch with u. And he also wants to invite his manager to have lunch with u too. So his manager and you (James) can talk about your plan.
Write to Don to tell him that u agree to lunch.. U agree to talk to his manager.
Ask him where u can have lunch. which restaurant? what time? what date (Monday or Saturday, ....)?