Just follow the steps in the image above.
or
https://support.patreon.com/hc/en-us/articles/212052266-How-do-I-receive-my-Discord-role-

--try this--
Step 1: Log out of Discord.
Step 2: Disconnect Discord from Patreon (If it's not connected skip this step.)
Step 3: Reconnect to Discord on Patreon.
Step 4: Log into Discord.
Step 5: ????
Step 6: Profit.