Break your overall plan into smaller sections, then when you are ready to work break those sections into manageable chunks, then concentrate on one at a time. “The way to eat an elephant is one bite at a time.”
Some people make a visual overview of the whole, so they can see where their current chunk fits in.
Find out how long you can concentrate for (which might be as short as 15 minutes). Design chunks to last that long.
Set your timer, concentrate on the chunk, and when the timer goes stop and take a brief minibreak to allow your brain to recover.
Tick the chunk off, then start the next chunk.
This technique helps you to make progress, even on days when you are struggling. You can revise your work next day.
Check that you have understood correctly e.g. ‘So the first thing is for me to …’
Do not rely on remembering verbal instructions. Ask for a written reminder, to which you can refer.
Some people make audio recordings, to which they can listen again.
If the instructions are about an activity in the future, you may want to create a reminder that you will see when you come to start the task. E.g. Put a post-it on a form ‘waiting for authorisation from X’.