Being a procedural text, most clauses in [4:2] take people as their point of departure… . Unmarked topical Theme selection is not deployed to scaffold [4:2]'s staging or development (although it does reflect its genre). Instead marked Themes, both phrasal and clausal, are used to stage the dog showing procedure.
 The clauses in (genuine) procedural texts take procedures — (typically material) processes — as their point of departure, and feature imperative mood (Halliday & Matthiessen 1999: 98; Halliday & Matthiessen 2014: 479). The clauses in text [4.2] take people as their point of departure, and feature indicative mood. This reflects the fact that this text is actually a recount of a procedure. A recount of a procedure is a recount, not a procedure.
These two text types differ in terms of the situation type they realise. The context of the recount text [4.2] is 'reporting', whereas the context of a procedural text is 'enabling' (Halliday & Matthiessen 2014: 219).
Halliday & Matthiessen (1999: 356):
The notion of procedure can be taken as a summary gloss of the domain; it is a macro-operation, consisting of a number of atomic micro-operations. It is dominated by procedures (algorithms, figures of doing) that lead to some specific goal: the dominant cause is purposive. An agent or agents try to produce, assemble, repair, etc..
From the interpersonal point of view, the notion of procedure can also be taken as a gloss on the interaction between the writer and the reader, it is a macro-proposal, consisting of a number of instructions or directions to the reader. A dependent clause in regressive clause nexus is not a marked topical Theme of a clause. See previous posts.