I'll guide you through the process of installing the library that contains SFE_BMP180.h and then you can see if you can apply the same process to the other library.
In your Google search, a highly ranged result should have been this page:
So let's say you had decided you wanted to install that library to see if it was the one your code was written for. The majority of Arduino libraries are hosted on GitHub, so the process of installing this library can be used to install many other libraries.
The first step is to go to the home page of the repository. At the top of the page, you can see some links: "LowPowerLab/SFE_BMP180". The first link is the user name of the person who owns the repository. If you click on that, you will go to their GitHub profile page, which is no what you want. The second link: "SFE_BMP180" is the name of the repository. If you click on this link, it takes you to the home page of the SFE_BMP180 repository, which is what you want. In this case, the Google link happened to already point to the home page of the repository so this step was unnecessary, but in other cases you'll end up with a link to a subpage of the repository and the following instructions only work from the home page.
GitHub repositories contain the up-to-date development work on the project. As a regular user (rather than a developer or beta tester), you will generally want to use a release version of the library, rather than the beta version, since the beta version is not as well tested as the release version. You'll see a bar on the repository home page that says something like this:
6 Commits 1 Branch 0 Releases 2 Contributors
The "0 Releases" link will take you to the releases page of the repository, which has links to download the .zip file of the library for each release. In this particular repository, the "0" part indicates the repository owner never bothered to make a release, so you're stuck using the beta version of the library. The beta version is downloaded like this:
- Click the "Clone or Download" button.
- From the menu that opens, click the "Download ZIP" button.
- Wait for the download to finish.
Now you have a .zip file that contains the contents of the repository in your download folder. It's time to install the library:
- (In the Arduino IDE) Sketch > Include Library > Add ZIP Library
- Select the downloaded file.
- Click the "Open" button.
- Wait for the teal bar on the Arduino IDE above the black console window to show the message "Library added to your libraries. Check "Include Library" Menu.
In some cases, the library installation will fail and it will instead say "Specified folder/zip file does not contain a valid library". Assuming the repository actually does contain an Arduino library, the problem is usually that the .zip file does not have the correct folder structure for installing from a .zip file. The Arduino IDE requires that the library folder is located directly under the root of the .zip file, not in a subfolder of the .zip file. In the case where the library author put the library in a subfolder of the repository, you can install it like this:
- Unzip the downloaded file.
- (In the Arduino IDE) Sketch > Include Library > Add ZIP Library
- Select the folder that contains the library.
- Click the "Open" button.
- Wait for the teal bar on the Arduino IDE above the black console window to show the message "Library added to your libraries. Check "Include Library" Menu.
As you can see, despite the menu name, Add ZIP Library can install libraries from folders as well as from .zip files.
Congratulations, you have now installed the library! More importantly, you now understand how to install any Arduino library you find on GitHub, which is an essential skill for every Arduino user.