Oanda's account structure is like this:
- Main Account
   - Sub-Account #1
   - Sub-Account #2

TS's account structure is like this:
- Account #1
- Account #2
- Account #3

So how do you set up Oanda sub-accounts in TS?

Firstly, set up your User in TS, using the Oanda username. Let's say the username is "Bob".

Now, each account or sub-account in Oanda has a different account number. You should create one TS account for each Oanda account or sub-account.

E.g. you have an Oanda account with username "Bob" and #123456789. That account has a sub-account #987654321.

In TS, create your Oanda user "Bob". Then create one TS account, with user "Bob" and account number #123456789. Then create another TS account, with user "Bob" and account number #987654321.

In summary, 1 Oanda account with 1 sub-account equals 2 accounts with the same User but different account numbers in TS.