Yes, do use PROCESS and add on in the regression analyses of SPSS. Hayes’ new book that came in 2018 explains multiple independent variable and multi levels within them. You can select model from the list given in the book and then use prescribed dialog boxes and bootstrap options.
Abdul Rehman ... if you don't have any guidelines to use SPSS or MLR for your analysis; then it would be more appropriate if you use CB-SEM or PLS-SEM for mediation analysis. As there is only one mediator, you have both options available i.e. CB-SEM and PLS-SEM. However, I find some first-order variables in your PRICE SATISFACTION variable; in that case, I would recommend you PLS-SEM using SMARTPLS version 3.2.8.