whats the best way to stay fit while waiting on my application is there a specific routine or?

From my experience as a soldier doing a range of fitness activity is best. Running is core fitness but vary with short interval training and some distance running so you don't get bored of doing the same run. The days between runs do something else like the gym or a circuit. Also split your rest days one during the week and one on a weekend, not together if you can help it. Finally look online for your local park run and if it is close by then attend on a Saturday morning, its free and competitive with all standards of runners. This is just an overview of the training I currently do.