Matters v Briefs: what is the difference?
A matter typically relates to one set of proceedings, or proposed proceedings.
A brief is the work to be done in relation to a particular matter. You might be briefed more than once in a particular matter.
For example, if you have a flourishing mentions practice, you might appear on a directions hearing. Then, a couple of months later, you are briefed to appear in the same matter, but on a directions hearing. For each directions hearing, you would add a brief, send an invoice, then close the brief. For the next directions hearing, you'd do the same process but on a new brief.
Here's another example. You're briefed to provide an advice on prospects of success in proposed proceedings. That is one brief in this matter. If the prospects of success are reasonable, you might be asked to draft or settle a statement of claim. That's a second brief in the same matter.