You have to declare what you earn through Guide Me Right, but it is not necessary to be registered with a VAT number to become a Local Friend.
Guide Me Right issue invoices to LF only for the matching IT service. Depending on your tax regime, you have to issue a receipt for occasional provision of services or an invoice (if you are registered with a VAT number) to a Guest.
If you are an amateur Local Friend, what you earn from Guide Me Right is classified as Occasional Provision beyond the cumulative limit of 5,000 €. It’s up to you to declare and to verify that you are in the yearly limit.
The amount you write in the receipt is the one paid by the Guest. Then, Guide Me Right issues an invoice for the matching IT service. Doing so, you have incomes (receipt) and outcomes (GMR invoice) and you register the amount you actually earn.