For your first swim, just try to get used to being in the water and swimming. All the best swimmers make it look easy because they are so relaxed. For your first swim, this is going to be your focus. Try to stay relaxed as possible.
10 minutes easy swim
10 minutes swim with pull buoy (a shaped foam block between your legs)
10 minutes swim
This is an easy run at a slow effort. If you need to run and walk for a bit, that is fine. Easy runs throughout the plan should be at a pace where you can hold a conversation with someone. If you have a heart rate monitor and know your zones, you should be in zones 1 or 2.
This is a slow gentle swim. No paddles but feel free to use a pull buoy
Enjoy doing a nice social run. This run isn't about time, it is about enjoying running with other people. One of the motivations of doing triathlon is running with other people who will encourage you and appreciate encouragement from you.
Most swim run events are on the fells where you need to get used to dealing with steep hills and uneven terrain.
To start to get you used to such terrain try a fast walk on the fells. If you feel confident, try running the down hill sections
This will be your first introduction to RPE. RPE is the rate of perceived effort. It is a scale from 1 -10 of your effort levels. So and RPE of 3 might be you doing something very slowly, such as a slow shuffle when running. An RPE of 10 will be a flat out sprint.
350m warm up
1 x 250 RPE 5 - 20 sec recovery
1 x 200 RPE 6 - 20 sec rec
1 x 150 RPE 7 - 15 sec rec
1 x 100 RPE 8 - 15 sec rec
1 x 50 RPE 9 - 15 sec rec
1 x 25 RPE 10 - 25 sec recovery
225m cool down
This is the triple M workout. You will run for 3 minutes at medium pace, then 3 minutes at moderate pace and finally 3 minutes at a mad pace which is as fast as you can manage. Have a 3 minute slow recovery jog, and then do it again.
If you find it too tough, just do it once through.