Tap and drag to pan around the screen to see more of the spreadsheet, just like in other iOS apps. To view the toolbar, tap the screen when a document is opened. To switch to edit mode in an Excel document, tap anywhere on the screen and select the pencil icon in the top right corner. Double tap in a cell to bring up the keyboard onto the screen to allow making edits.
Open a different worksheet in the file by tapping the name of the sheet at the bottom of the document.