If you haven't already, you can download LogTen Pro for iOS here.
Before you can purchase a subscription, you'll be asked to login with your Coradine Account, so please Create a Coradine Account if you have not yet already. Your Coradine Account will allow you to use your LogTen Pro subscription on multiple devices depending on your subscription choice, or restore it if anything were to happen to your current device.
You can view and purchase the different subscription options by going to the More tab, then select Settings, and Store.
Note: Prices will vary depending on your App Store region. Please check the application for the prices in your locale.
Select one of the subscription options and you will see additional details about it on the next screen. At the bottom of the screen tap Buy and the In-App Purchase process will start. As with any other In-App purchase, you may be prompted to login to the iTunes Store with your Apple ID.
After purchasing, your subscription will appear in the Purchased section of the Store tab, and display the date it is due to renew. You can also use the same subscription for LogTen Pro on a total of five iOS devices, and if you purchased one of the cross-platform subscription, up to five Macs. All you need to do is login with the same Coradine Account that was used to purchase your subscription, and your other device will automatically be authorized on your account.