01 See #TiSDD 8.3, Service design and software development, for an example of how a research wall is used to connect different service design activities of research, ideation, prototyping, and implementation. There are many similar approaches with different names; for example, the “Saturate and Group” method from IDEO/d.school.
02 See the octopus clustering method in #TiSDD 6.4, Ideation methods, for a detailed description.
You can imagine a research wall  as a more complex version of how detectives structure their crime scene data in many thrillers (think of any CSI episode). You’ll find many types of data on these walls (quotes, photos, screenshots of websites or videos, statistics, artifacts, etc.).
A research wall enables you to identify patterns within your data, while also providing a place to share your research with others as it develops. Often, you start synthesizing data by simply clustering it according to specific categories or by creating a simple mind map of your dataset. Using an interactive convergent method, such as octopus clustering, is usually a good start. 
You can consider the various patterns you identify as intermediate research outcomes. These can be then further explored, visualized, or condensed with tools like personas, journey maps, system maps, key insights, jobs to be done, user stories, or research reports. However, before researchers start working with these tools, they usually create some form of intermediate-level outputs – perhaps visual representations that describe patterns in the data. Often these patterns also lead to new or modified assumptions that need further research. Look for contradictions to your initial hypothesis, and start “building your case” with the support of user verbatims, photos, and audio and/or video recordings. Many of these intermediate insights can be illustrated with simple diagrams and sketches that will be useful when presenting them to your team and beyond.