Stick to chronological order
A key part of many tribunal documents is an account of what has happened. Witness statements are the most obvious example, but, ET1s, ET3s, written submissions and notices of appeal will also contain a recitation of the facts.
Unless there is a very good reason not to, this account should be given in chronological order.
Sometimes it is tempting to use a different approach. In a bullying case, you might deal with what Mr Smith did, what Ms Jones did, then what Mr Adam did. Where there are a number of different jurisdiction, you might deal with each jurisdiction in turn.
This is almost always a mistake. The first thing that the tribunal will want to do is to figure out what has happened. It is easiest and most natural for them to approach this in chronological order. Any other approach, no matter how initially attractive, is likely to become confusing and difficult.
Of course, once the facts have been set out, it is useful to discuss and analyse them in other ways. This is easily done by referring to the chronological account. For example, in a case of multiple claims you might write, in the second part of your submission:
34. The claimant complains of indirect sex discrimination, harassement and victimisation as follows:
35. Indirect Discrimination The respondent applied a rule, that all employees had to staff both morning and evening sessions, which put women, including the claimant, at a disadvantage when compared with their male collegues. See paragraphs 4-13 and 21-26.
36. Harassment When the claimant complained of this rule, her manager and male collegues belittled her work, stopped including her in social events and made frequent comments to the effect that, as a women, she was not capable of doing her work as well as the men. See paragraphs 5-20 and 31-33.
37. Victimisation After the claimant complained to management about the discrimination she had suffered, she was refused a promotion to Senior Officer. See paragraphs 27-30.
Note that the references back to the chronological account include a brief summary of what is being referred to. Writing “harassment, see paragraphs 5-20 and 31-33” is just as confusing as taking the events out of order.