Hello mate, no problems at all... happy to help
For the TS server if you come to RaceDepartment.com and you should see on the left hand side the TS screen (see screenshot below)
View attachment 181020
If you click where it says "racedepartment.com" that will load up the TS application on your machine. All you will need to do then will be to put the password in and you'll be in the RD teamspeak! Just move yourself to the channel relevant to the game / server where you will be racing.
Regarding finding the server in Assetto Corsa, firstly make sure all the options are selected on the lobby screen (I've taken the screenshot off google so it might not represent the full modern screen, but you get the idea.
View attachment 181021
Where I've put the arrows you want to make sure all the options are enabled. So you want to be able to see servers that are password protected in particular. Once these are done, just type in racedepartment in the search field and you should find it! Once you've picked it, enter the password and you should be away to go
If you are still struggling on race day, just log yourself in to TS and someone will be more than happy to help you out I'm sure.
Sorry to waffle on a bit, hope this helps buddy
Cheers