To use the SP Flash tool you need to have a scatter file. One easy way to find that is to look out for other devices that use the same chipset but the manufacturer releases the firmware file including the scatter file one such manufacturer is Xiaomi but you may find other manufacturers as well.
Samsung Galaxy A34 uses Dimensity 1080[MT6877v] and here is the list of other devices that use this chip as well:
Devices come in two kinds, eMMC and UFS. eMMC is just an SD card but in a package of a chip which then is called an embedded SD card or eMMC. Others come with UFS storage which is NAND flash in fancy words. You can determine your device type by looking at the specs. For A34 that is UFS 2.2.
There’s a PIT (Partition Information Table) file inside all Samsung firmware. This file includes all partition starting addresses. Don’t know how to read it yet though
By DRAM option, choose how the file was first copied to the device and then write to the actual location. Both should work in normal conditions, SRAM used if DRAM has issues, pro during R&D.