Here is a guide you can follow:
Enable USB Debugging Mode. For most phones, you can find the option on your phone through: Settings > Developer Options > USB Debugging. If you can't find the option, please type "phone model + enable USB Debugging mode" in search engines to get detailed guides.
Root your phone to get root privilege. Rooting means gaining root access to your device, so that the program gets permission to scan your phone. Since there are so many Android OS versions and phone brands, it's hard to find a single tool that can root all devices in high successful rate. Here are some commonly used root tools: iRoot, Kingo Root, oneclickroot, Root Genius, etc.
Connect phone to computer via USB cable. Please make sure it is well connected, otherwise recovery result will be disturbed.
Step 1: Launch Eassos Android Data Recovery software, and click "Refresh Device" to detect the device. The program will show storage devices in your phone and display internal built-in memory (internal storage) and memory card separately.
Step 2: Select storage device and click "Next". Then this Android data recovery software will make image and search for lost data automatically.
Step 3: After a while the image is created and the software starts to scan it and display lost files.
Step 4: Preview files. Double-click file to open it and view its content and files like photos, video, audio, documents, etc. can be previewed.
Step 5: Select files you want to recover and click "Recover" button to save them to a secure location. Alternatively, after selecting needed files, you can right click mouse and copy files with context menu.