Welcome. Lots and lots of excellent advice and suggestions for you thus far. You may also keep in mind the Fortran Wiki site for information: Fortran Wiki
If you’re seeking an easily accessible step-by-step introduction that can help you get going with commonly used features up to Fortran 2008, this guide is rather good: Introduciton to Programming using Fortran 95/2003/2008
Note the book by Clerman and Spector on “Modern Fortran: Style and Usage” is excellent. It provides a lot of details on modernizing legacy FORTRAN code in addition to good practices in new code. So does the book by Hanson and Hopkins: https://www.amazon.com/Numerical-Computing-Fortran-Applied-Mathematics/dp/1611973112
And given your background in Engineering, the book by Chapman is also useful: https://www.amazon.com/Fortran-Scientists-Engineers-Stephen-Chapman-ebook/dp/B06XCTY8KR