HOTP Token from a third party

i am new by

I am from germany an we will use The most users work with the app in future, bute some with token. I dont understant right, to use token from a third party.

When i buy a token, i have unterstand, the token uses sh1 algorithmus. The reseller offers the token with “seed-programming”. Do i need this?

i will use first time : OTP c200 „H41
Which time is recommend, 30 or 60 seconds?

Sorry, but its my first time to learn 2FA. Can anyone help me to find the right answers?

Thanks for your support.