If your first patent application was a UK patent application and if you wish to continue further with it, then there will be a deadline of one year from the filing date of that application to file claims and an abstract, and a request for search, if any of these have not already been filed.
If there are no unusual circumstances, then one year from the filing date of your first patent application will also be the deadline for filing any later patent applications in the UK or Paris Convention countries abroad which need to claim priority from your first patent application (and any revised patent applications filed during the intervening year).
As this is the final opportunity which you will have to file patent applications which claim priority from your first patent application, it is important to have made a decision well in advance of this date as to whether and where you will seek international patent protection.
This one year deadline is also the final, convenient opportunity to file revised patent applications which include additional information about your idea and revise the scope of protection which you seek. Again, you should think about whether there have been any important revisions to your idea well before this date. (Note that any claims to a revision of the invention which are included for the first time in a new patent application will not be entitled to claim priority from any earlier patent application(s)).