chore: update doc lammps isntallation

doc/install/install-from-source.md

@@ -250,10 +250,23 @@ If you specify `-DUSE_TF_PYTHON_LIBS=FALSE`, you need to give the location where
 
 I assume you have installed the PyTorch (either Python or C++ interface) to `$torch_root`, then execute CMake
 ```bash
-cmake -DENABLE_PYTORCH=TRUE -DCMAKE_PREFIX_PATH=$torch_root -DCMAKE_INSTALL_PREFIX=$deepmd_root ..
+cmake -DENABLE_PYTORCH=TRUE -DCMAKE_PREFIX_PATH=$torch_root -DCMAKE_INSTALL_PREFIX=$deepmd_source_dir ..
 ```
-:::
 
+Alternatively, one can use the installation scripts provided by DeepMD-kit by executing the following commands:
+```bash
+export CMAKE_PREFIX_PATH=$libtorch_root
+```
+and if use GPU, add
+```bash
+export DP_VARIANT=cuda
+```
+then
+
+```bash
+$deepmd_source_dir/source/install/build_cc.sh
+```
+:::
 ::::
 
 One may add the following arguments to `cmake`:

doc/install/install-lammps.md

@@ -5,7 +5,13 @@ There are two ways to install LAMMPS: the built-in mode and the plugin mode. The
 ## Install LAMMPS's DeePMD-kit module (built-in mode)
 Before following this section, [DeePMD-kit C++ interface](install-from-source.md) should have be installed.
 
-DeePMD-kit provides a module for running MD simulations with LAMMPS. Now make the DeePMD-kit module for LAMMPS.
+DeePMD-kit provides an easy installation script, one can simply run the following command to isntall LAMMPS:
+
+```bash
+$deepmd_source_dir/source/install/build_lammps.sh
+```
+
+Alternatively, manual installation is also supported. DeePMD-kit provides a module for running MD simulations with LAMMPS. Now make the DeePMD-kit module for LAMMPS.
 
 ```bash
 cd $deepmd_source_dir/source/build