How to add trail running activity profile on my Garmin Forerunner 735XT?

Hello, thank you for your reply, but that is my problem, I do not see trail run in my activity profiles :( 

You don't see it because it's not available by default. You have to add it to your profile list. The manual page I linked above shows you how to do it.

Hello tmk2. Sorry for not detailing in my previous post, but when I go to add an activity profile that is not already loaded in my device, I do now have a Trail run activity profile.

Except the already known Garmin activities like Run, Swim, etc., I have Multisport, XC Ski, Cardio, Strength, Row, Cardio.

Ok, I understand. This is odd. It should be there. I sold my FR735XT some time ago, but I clearly remember having the Trail Run profile.

6344420 said:

Forerunner does not have trail running profile

I'm 100% sure this is incorrect. I've used the FR735XT for over 4 years, and I had a "Trail run" profile, a native one, not an IQ app.

let's wait for someone else to confirm/deny this information but I am a trail runner with a Forerunner 735XT and it does not have this profile. 

First you have to choose Running, and after setting color and name there are options (types of run) and there you pick Trail running.