If it's a "No" to either… you might want to change that, to avoid
confusion later on.

If it's a "Yes" to both… please read on.

A. If you've linked your YouTube account to your Google account:
   1. Sign into YouTube.com
   2. Click on Community Help Forums link on YouTube.com
   3. In Forums, click on "Join this group"
   4. You'll see a summary of your status and your username (The
Groups nickname will match your YouTube.com username)
   5. Confirm that status and you can begin posting
   6. In future posts, you can just begin posting and won't see that
summary

B. If you've not yet linked your YouTube account to your Google
account:
   1. Sign into YouTube.com
   2. Click on Community Help Forums link on YouTube.com
   3. In Forums, click on "Join this group"
   4. You're asked to sign up for a Google account
   5. Create the Google account and sign in to post

C.  If you have a Google account, but no YouTube account:
   1. Sign up for a YouTube account
   2. Click on Community Help Forums link on YouTube.com
   3. In Forums, click on "Join this group"
   4. When prompted, sign into Google account
   5. You'll see a summary of your status and your username (The
Groups nickname will match  your YouTube.com username)
   6. Confirm that status and you can begin posting
   7. In future posts, you can just begin posting and won't see that
summary

D. Don't have a YouTube account or a Google account?
   1. Sign up for a YouTube account
   2. Sign into YouTube.com
   3. Click on Community Help Forums link on YouTube.com
   4. In Forums, click on "Join this group"
   5. You're asked to sign up for a Google account
   6. Create the Google account and sign in to post