Update colmap install guide (#696)

docs/quickstart/custom_dataset.md

@@ -30,11 +30,18 @@ ns-train instant-ngp nerfstudio-data --data {PROCESSED_DATA_DIR}
 
 ### Installing COLMAP
 
-The COLMAP maintainers recommend using VCPKG to install COLMAP. If the following command do not work, please refer to the [COLMAP installation guide](https://colmap.github.io/install.html) for additional installation methods. COLMAP install issues are common! Feel free to ask for help in on our [Discord](https://discord.gg/NHGtYRAW).
+There are many ways to install COLMAP, unfortunately it can sometimes be a bit finicky. If the following commands do not work, please refer to the [COLMAP installation guide](https://colmap.github.io/install.html) for additional installation methods. COLMAP install issues are common! Feel free to ask for help in on our [Discord](https://discord.gg/NHGtYRAW).
 
 ::::::{tab-set}
 :::::{tab-item} Linux
 
+We recommend trying `apt`:
+
+```
+sudo apt install colmap
+```
+
+If that doesn't work, you can try VKPG:
 ::::{tab-set}
 :::{tab-item} CUDA
 
@@ -58,6 +65,8 @@ cd vcpkg
 :::
 ::::
 
+If that doesn't work, you will need to build from source. Refer to the [COLMAP installation guide](https://colmap.github.io/install.html) for details.
+
 :::::
 
 :::::{tab-item} OSX