With the advent of the Apple II in 1977 -along with microcomputers from other vendors (such as TRS 80s and Commodore PETs)- K-12 schools began in earnest the process of putting digital technology together with students. Schools often started by converting an existing classroom to a computer lab. The early microcomputers were not networked, did not have hard drives, and had less than 128,000 bytes of RAM. A typical MP3 song file today is 3,000,000 bytes in size. All the RAM in all the computers in a early computer lab would not have been able to store a single song file.
WISIWYG (What You See is What You Get) applications did not exist for these computers. In fact, there were very few applications so a lot of computer lab use focused on programming in BASIC. More students learned computer programming during these years than at any time before or since. Teaching programming became controversial as many parents felt it was equivalent to teaching auto mechanics. Parents argued that their children didn't need to know how to fix cars, they just needed to know how to use them. In other words, there was pressure to make intro computer courses more like drivers ed.
In the early 1980s a number of productivity applications became available. Bank Street Writer, PFS WorkMates and AppleWorks were apps developed with the K-12 population in mind. It was not unusual for schools to try a number of different productivity applications over a period of years before settling on a product. Many schools using Apples eventually chose AppleWorks as it combined word processing, spreadsheet, database, and terminal applications in an effective and clear manner.
Since lab computers did not have hard drives, applications and data were stored on 5.25" floppy disks. Most computers were configured with two floppy disk drives, one of which held the disk with the application software, the other held the disk with the user's data files. Bins were used to hold the disks. Each class would usually have their own bin of disks. (Does anyone have some pictures handy of computer labs of this time period?)
A few adventureous administrators and admin assistants used early personal computers. These computers were usually not networked. Most printers were dot-matrix. Connecting to online communities like AOL or CompuServe (the Internet was not a factor yet at the K-12 level) was done via modem.
Teachers did not have computers at their desks for their own use. Only a few classrooms had their own computers. It was common to have a computer on a cart which could be wheeled from classroom to classroom. Kind of that time's equivalent of today's cart of laptops.
Looking back this seems kind of like a dark age of school computing, but at the time it was very exciting and full of promise.