There are many useful yet free resources like tutorials and blogs in a sequential manner to help you learn SAP FICO at your pace. Some of them are mentioned here:
SAP FICO Tutorial
SAP S4HANA Finance
Once you are well equipped with Theoretical knowledge to go with some hands-on:
Thereafter when theory and practice are on tips, refer to the SAP FICO interview questions.
Note: this only gives an idea of the type of questions that you may face in your interview.
Moving on, if you feel to add one more feather in your cap, enroll yourself in an end-to-end certification training to get certified. The certification adds value to your resume. For that check out the SAP FICO certification course.