Make sure that the excursion leader signs the excursion days in your field pass. Once you have completed the required number of days, your field pass must be signed by the respective module coordinator (preferably during the lecture period, as the coordinator is probably not in the office during the semester break).
If you have more than the required number of days for your Bachelor's degree, the excess days may be credited for your Master's studies.
Excursion days from other universities (e.g. from Erasmus exchanges) can be credited for your excursion module. For this, a signed statement from the excursion leader stating the number of days and a brief description of the excursion, must be submitted to the module coordinator.