You will almost certainly incur expenses prior to incorporating your company, and these should be met initially from your own pocket and claimed at a later date.
You may claim for as far back as seven years, but everything you claim must be normal expenses that relate both to the business of the company and the period of time that you have been pursuing the objectives of the company, and should be supported by invoices or receipts.
Capital items, such as IT equipment, that are for use in the company may be brought into the company at any time, provided it is introduced at market value.
Do not loan any funds to your company or draw any expenses out of your company until you receive your first income. If, in the event you return to full time employment or close your company without ever having traded, it is simpler to do so without there having been any transactions.